#ifndef __TextureUnitState_H__
#define __TextureUnitState_H__

#include "U2PreRequest.h"
#include "U2MemoryAllocatorConfig.h"
#include "U2Common.h"
#include "U2BlendMode.h"
#include "U2Matrix4.h"
#include "U2IteratorWrappers.h"
#include "U2StringUtil.h"
#include "U2Texture.h"
#include "U2Controller.h"
#include "U2Math.h"


U2EG_NAMESPACE_BEGIN


class U2Frustum;


/** Class representing the state of a single texture unit during a Pass of a
    Technique, of a Material.
@remarks
    Texture units are pipelines for retrieving texture data for rendering onto
    your objects in the world. Using them is common to both the fixed-function and 
    the programmable (vertex and fragment program) pipeline, but some of the 
    settings will only have an effect in the fixed-function pipeline (for example, 
    setting a texture rotation will have no effect if you use the programmable
    pipeline, because this is overridden by the fragment program). The effect
    of each setting as regards the 2 pipelines is commented in each setting.
@par
    When I use the term 'fixed-function pipeline' I mean traditional rendering
    where you do not use vertex or fragment programs (shaders). Programmable 
    pipeline means that for this pass you are using vertex or fragment programs.
*/
class _U2Share TextureUnitState : public TextureUnitStateAlloc
{
    friend class U2RenderSystem;

public:
    /** Definition of the broad types of texture effect you can apply to a texture unit.
    @note
        Note that these have no effect when using the programmable pipeline, since their
        effect is overridden by the vertex / fragment programs.
    */
    enum TextureEffectType
    {
        /// Generate all texture coords based on angle between camera and vertex
        ET_ENVIRONMENT_MAP,
        /// Generate texture coords based on a frustum
        ET_PROJECTIVE_TEXTURE,
        /// Constant u/v scrolling effect
        ET_UVSCROLL,
		/// Constant u scrolling effect
        ET_USCROLL,
		/// Constant u/v scrolling effect
        ET_VSCROLL,
        /// Constant rotation
        ET_ROTATE,
        /// More complex transform
        ET_TRANSFORM

    };

    /** Enumeration to specify type of envmap.
    @note
        Note that these have no effect when using the programmable pipeline, since their
        effect is overridden by the vertex / fragment programs.
    */
    enum EnvMapType
    {
        /// Envmap based on vector from camera to vertex position, good for planar geometry
        ENV_PLANAR,
        /// Envmap based on dot of vector from camera to vertex and vertex normal, good for curves
        ENV_CURVED,
        /// Envmap intended to supply reflection vectors for cube mapping
        ENV_REFLECTION,
        /// Envmap intended to supply normal vectors for cube mapping
        ENV_NORMAL
    };

    /** Useful enumeration when dealing with procedural transforms.
    @note
        Note that these have no effect when using the programmable pipeline, since their
        effect is overridden by the vertex / fragment programs.
    */
    enum TextureTransformType
    {
        TT_TRANSLATE_U,
        TT_TRANSLATE_V,
        TT_SCALE_U,
        TT_SCALE_V,
        TT_ROTATE
    };

    /** Texture addressing modes - default is TAM_WRAP.
    @note
        These settings are relevant in both the fixed-function and the
        programmable pipeline.
    */
    enum TextureAddressingMode
    {
        /// Texture wraps at values over 1.0
        TAM_WRAP,
        /// Texture mirrors (flips) at joins over 1.0
        TAM_MIRROR,
        /// Texture clamps at 1.0
        TAM_CLAMP,
        /// Texture coordinates outside the range [0.0, 1.0] are set to the border colour
        TAM_BORDER
    };

	/** Texture addressing mode for each texture coordinate. */
	struct UVWAddressingMode
	{
		TextureAddressingMode u, v, w;
	};

    /** Enum identifying the frame indexes for faces of a cube map (not the composite 3D type.
    */
    enum TextureCubeFace
    {
        CUBE_FRONT = 0,
        CUBE_BACK = 1,
        CUBE_LEFT = 2,
        CUBE_RIGHT = 3,
        CUBE_UP = 4,
        CUBE_DOWN = 5
    };

    /** Internal structure defining a texture effect.
    */
    struct TextureEffect {
        TextureEffectType type;
        int subtype;
        u2real arg1, arg2;
        WaveformType waveType;
        u2real base;
        u2real frequency;
        u2real phase;
        u2real amplitude;
        Controller<u2real>* controller;
        const U2Frustum* frustum;
    };

    /** Texture effects in a multimap paired array
    */
    typedef std::multimap<TextureEffectType, TextureEffect> EffectMap;

    /** Default constructor.
    */
    TextureUnitState(/* Pass* parent */const U2String& resourceGroup);

    TextureUnitState(/* Pass* parent, */const U2String& resourceGroup, const TextureUnitState& oth );

    TextureUnitState & operator = ( const TextureUnitState& oth );

    /** Default destructor.
    */
    ~TextureUnitState();

    /** Name-based constructor.
    @param
    name The basic name of the texture e.g. brickwall.jpg, stonefloor.png
    @param
    texCoordSet The index of the texture coordinate set to use.
    */
	TextureUnitState( /* Pass* parent, */const U2String& resourceGroup, const U2String& texName, unsigned int texCoordSet = 0);

    /** Get the name of current texture image for this layer.
    @remarks
    This will either always be a single name for this layer,
    or will be the name of the current frame for an animated
    or otherwise multi-frame texture.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    const U2String& getTextureName(void) const;

    /** Sets this texture layer to use a single texture, given the
    name of the texture to use on this layer.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    void setTextureName( const U2String& name, TextureType ttype = TEX_TYPE_2D);

    /** Sets this texture layer to use a single texture, given the
    pointer to the texture to use on this layer.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    void setTexture( const U2TexturePtr& texPtr);

	/** Sets this texture layer to use a combination of 6 texture maps, each one relating to a face of a cube.
    @remarks
    Cubic textures are made up of 6 separate texture images. Each one of these is an orthogonal view of the
    world with a FOV of 90 degrees and an aspect ratio of 1:1. You can generate these from 3D Studio by
    rendering a scene to a reflection map of a transparent cube and saving the output files.
    @par
    Cubic maps can be used either for skyboxes (complete wrap-around skies, like space) or as environment
    maps to simulate reflections. The system deals with these 2 scenarios in different ways:
    <ol>
    <li>
    <p>
    for cubic environment maps, the 6 textures are combined into a single 'cubic' texture map which
    is then addressed using 3D texture coordinates. This is required because you don't know what
    face of the box you're going to need to address when you render an object, and typically you
    need to reflect more than one face on the one object, so all 6 textures are needed to be
    'active' at once. Cubic environment maps are enabled by calling this method with the forUVW
    parameter set to true, and then calling setEnvironmentMap(true).
    </p>
    <p>
    Note that not all cards support cubic environment mapping.
    </p>
    </li>
    <li>
    <p>
    for skyboxes, the 6 textures are kept separate and used independently for each face of the skybox.
    This is done because not all cards support 3D cubic maps and skyboxes do not need to use 3D
    texture coordinates so it is simpler to render each face of the box with 2D coordinates, changing
    texture between faces.
    </p>
    <p>
    Skyboxes are created by calling SceneManager::setSkyBox.
    </p>
    </li>
    </ul>
    @note
    Applies to both fixed-function and programmable pipeline.
    @param
    name The basic name of the texture e.g. brickwall.jpg, stonefloor.png. There must be 6 versions
    of this texture with the suffixes _fr, _bk, _up, _dn, _lf, and _rt (before the extension) which
    make up the 6 sides of the box. The textures must all be the same size and be powers of 2 in width & height.
    If you can't make your texture names conform to this, use the alternative method of the same name which takes
    an array of texture names instead.
    @param
    forUVW Set to true if you want a single 3D texture addressable with 3D texture coordinates rather than
    6 separate textures. Useful for cubic environment mapping.
    */
    void setCubicTextureName( const U2String& name, bool forUVW = false );

    /** Sets this texture layer to use a combination of 6 texture maps, each one relating to a face of a cube.
    @remarks
    Cubic textures are made up of 6 separate texture images. Each one of these is an orthogonal view of the
    world with a FOV of 90 degrees and an aspect ratio of 1:1. You can generate these from 3D Studio by
    rendering a scene to a reflection map of a transparent cube and saving the output files.
    @par
    Cubic maps can be used either for skyboxes (complete wrap-around skies, like space) or as environment
    maps to simulate reflections. The system deals with these 2 scenarios in different ways:
    <ol>
    <li>
    <p>
    For cubic environment maps, the 6 textures are combined into a single 'cubic' texture map which
    is then addressed using 3D texture coordinates. This is required because you don't know what
    face of the box you're going to need to address when you render an object, and typically you
    need to reflect more than one face on the one object, so all 6 textures are needed to be
    'active' at once. Cubic environment maps are enabled by calling this method with the forUVW
    parameter set to true, and then calling setEnvironmentMap(true).
    </p>
    <p>
    Note that not all cards support cubic environment mapping.
    </p>
    </li>
    <li>
    <p>
    For skyboxes, the 6 textures are kept separate and used independently for each face of the skybox.
    This is done because not all cards support 3D cubic maps and skyboxes do not need to use 3D
    texture coordinates so it is simpler to render each face of the box with 2D coordinates, changing
    texture between faces.
    </p>
    <p>
    Skyboxes are created by calling SceneManager::setSkyBox.
    </p>
    </li>
    </ul>
    @note
    Applies to both fixed-function and programmable pipeline.
    @param
    names The 6 names of the textures which make up the 6 sides of the box. The textures must all 
	be the same size and be powers of 2 in width & height.
	Must be an Ogre::U2String array with a length of 6 unless forUVW is set to true.
    @param
    forUVW Set to true if you want a single 3D texture addressable with 3D texture coordinates rather than
    6 separate textures. Useful for cubic environment mapping.
    */
    void setCubicTextureName( const U2String* const names, bool forUVW = false );

    /** Sets this texture layer to use a combination of 6 texture maps, each one relating to a face of a cube.
    @remarks
    Cubic textures are made up of 6 separate texture images. Each one of these is an orthogonal view of the
    world with a FOV of 90 degrees and an aspect ratio of 1:1. You can generate these from 3D Studio by
    rendering a scene to a reflection map of a transparent cube and saving the output files.
    @par
    Cubic maps can be used either for skyboxes (complete wrap-around skies, like space) or as environment
    maps to simulate reflections. The system deals with these 2 scenarios in different ways:
    <ol>
    <li>
    <p>
    for cubic environment maps, the 6 textures are combined into a single 'cubic' texture map which
    is then addressed using 3D texture coordinates. This is required because you don't know what
    face of the box you're going to need to address when you render an object, and typically you
    need to reflect more than one face on the one object, so all 6 textures are needed to be
    'active' at once. Cubic environment maps are enabled by calling this method with the forUVW
    parameter set to true, and then calling setEnvironmentMap(true).
    </p>
    <p>
    Note that not all cards support cubic environment mapping.
    </p>
    </li>
    <li>
    <p>
    for skyboxes, the 6 textures are kept separate and used independently for each face of the skybox.
    This is done because not all cards support 3D cubic maps and skyboxes do not need to use 3D
    texture coordinates so it is simpler to render each face of the box with 2D coordinates, changing
    texture between faces.
    </p>
    <p>
    Skyboxes are created by calling SceneManager::setSkyBox.
    </p>
    </li>
    </ul>
    @note
    Applies to both fixed-function and programmable pipeline.
    @param
    pTextures The 6 pointers to the textures which make up the 6 sides of the box. The textures must all 
	be the same size and be powers of 2 in width & height.
	Must be an Ogre::U2TexturePtr array with a length of 6 unless forUVW is set to true.
    @param
    forUVW Set to true if you want a single 3D texture addressable with 3D texture coordinates rather than
    6 separate textures. Useful for cubic environment mapping.
    */
    void setCubicTexture( const U2TexturePtr* const texPtrs, bool forUVW = false );

	/** Sets the names of the texture images for an animated texture.
    @remarks
    Animated textures are just a series of images making up the frames of the animation. All the images
    must be the same size, and their names must have a frame number appended before the extension, e.g.
    if you specify a name of "wall.jpg" with 3 frames, the image names must be "wall_0.jpg", "wall_1.jpg"
    and "wall_2.jpg".
    @par
    You can change the active frame on a texture layer by calling the setCurrentFrame method.
    @note
    If you can't make your texture images conform to the naming standard laid out here, you
    can call the alternative setAnimatedTextureName method which takes an array of names instead.
    @note
    Applies to both fixed-function and programmable pipeline.
    @param
    name The base name of the textures to use e.g. wall.jpg for frames wall_0.jpg, wall_1.jpg etc.
    @param
    numFrames The number of frames in the sequence.
    @param
    duration The length of time it takes to display the whole animation sequence, in seconds.
    If 0, no automatic transition occurs.
    */
    void setAnimatedTextureName( const U2String& name, unsigned int numFrames, u2real duration = 0 );

    /** Sets the names of the texture images for an animated texture.
    @remarks
    This an alternative method to the one where you specify a single name and let the system derive
    the names of each frame, incase your images can't conform to this naming standard.
    @par
    Animated textures are just a series of images making up the frames of the animation. All the images
    must be the same size, and you must provide their names as an array in the first parameter.
    You can change the active frame on a texture layer by calling the setCurrentFrame method.
    @note
    If you can make your texture images conform to a naming standard of basicName_frame.ext, you
    can call the alternative setAnimatedTextureName method which just takes a base name instead.
    @note
    Applies to both fixed-function and programmable pipeline.
    @param
    names Pointer to array of names of the textures to use, in frame order.
    @param
    numFrames The number of frames in the sequence.
    @param
    duration The length of time it takes to display the whole animation sequence, in seconds.
    If 0, no automatic transition occurs.
    */
    void setAnimatedTextureName( const U2String* const names, unsigned int numFrames, u2real duration = 0 );

    /** Returns the width and height of the texture in the given frame.
    */
    std::pair< size_t, size_t > getTextureDimensions( unsigned int frame = 0 ) const;

    /** Changes the active frame in an animated or multi-image texture.
    @remarks
    An animated texture (or a cubic texture where the images are not combined for 3D use) is made up of
    a number of frames. This method sets the active frame.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    void setCurrentFrame( unsigned int frameNumber );

    /** Gets the active frame in an animated or multi-image texture layer.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    unsigned int getCurrentFrame(void) const;

    /** Gets the name of the texture associated with a frame number.
        Throws an exception if frameNumber exceeds the number of stored frames.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    const U2String& getFrameTextureName(unsigned int frameNumber) const;

    /** Sets the name of the texture associated with a frame.
    @param name The name of the texture
    @param frameNumber The frame the texture name is to be placed in
    @note
    Throws an exception if frameNumber exceeds the number of stored frames.
    Applies to both fixed-function and programmable pipeline.
    */
    void setFrameTextureName(const U2String& name, unsigned int frameNumber);

    /** Add a Texture name to the end of the frame container.
    @param name The name of the texture
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    void addFrameTextureName(const U2String& name);
    /** deletes a specific texture frame.  The texture used is not deleted but the
        texture will no longer be used by the Texture Unit.  An exception is raised
        if the frame number exceeds the number of actual frames.
    @param frameNumber The frame number of the texture to be deleted.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    void deleteFrameTextureName(const size_t frameNumber);
    /** Gets the number of frames for a texture.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    unsigned int getNumFrames(void) const;


	/** The type of unit to bind the texture settings to. */
	enum BindingType
	{
		/** Regular fragment processing unit - the default. */
		BT_FRAGMENT = 0,
		/** Vertex processing unit - indicates this unit will be used for 
			a vertex texture fetch.
		*/
		BT_VERTEX = 1
	};
	/** Enum identifying the type of content this texture unit contains.
	*/
	enum ContentType
	{
		/// Normal texture identified by name
		CONTENT_NAMED = 0,
		/// A shadow texture, automatically bound by engine
		CONTENT_SHADOW = 1,
		/// A compositor texture, automatically linked to active viewport's chain
		CONTENT_COMPOSITOR = 2
	};

	/** Sets the type of unit these texture settings should be bound to. 
	@remarks
		Some render systems, when implementing vertex texture fetch, separate
		the binding of textures for use in the vertex program versus those
		used in fragment programs. This setting allows you to target the
		vertex processing unit with a texture binding, in those cases. For
		rendersystems which have a unified binding for the vertex and fragment
		units, this setting makes no difference.
	*/
	void setBindingType(BindingType bt);

	/** Gets the type of unit these texture settings should be bound to.  
	*/
	BindingType getBindingType(void) const;

	/** Set the type of content this TextureUnitState references.
	@remarks
		The default is to reference a standard named texture, but this unit
		can also reference automated content like a shadow texture.
	*/
	void setContentType(ContentType ct);
	/** Get the type of content this TextureUnitState references. */
	ContentType getContentType(void) const;

    /** Returns true if this texture unit is either a series of 6 2D textures, each
        in it's own frame, or is a full 3D cube map. You can tell which by checking
        getTextureType.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    bool isCubic(void) const;

    /** Returns true if this texture layer uses a composite 3D cubic texture.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    bool is3D(void) const;

    /** Returns the type of this texture.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    TextureType getTextureType(void) const;

    /** Sets the desired pixel format when load the texture.
    */
    void setDesiredFormat(PixelFormat desiredFormat);

    /** Gets the desired pixel format when load the texture.
    */
    PixelFormat getDesiredFormat(void) const;

    /** Sets how many mipmaps have been requested for the texture.
	*/
    void setNumMipmaps(int numMipmaps);

    /** Gets how many mipmaps have been requested for the texture.
	*/
    int getNumMipmaps(void) const;

	/** Sets whether this texture is requested to be loaded as alpha if single channel
	*/
    void setIsAlpha(bool isAlpha);

	/** Gets whether this texture is requested to be loaded as alpha if single channel
	*/
    bool getIsAlpha(void) const;

	/// @copydoc Texture::setHardwareGammaEnabled
	void setHardwareGammaEnabled(bool enabled);
	/// @copydoc Texture::isHardwareGammaEnabled
	bool isHardwareGammaEnabled() const;

    /** Gets the index of the set of texture co-ords this layer uses.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    unsigned int getTextureCoordSet(void) const;

    /** Sets the index of the set of texture co-ords this layer uses.
    @note
    Default is 0 for all layers. Only change this if you have provided multiple texture co-ords per
    vertex.
    @note
    Applies to both fixed-function and programmable pipeline.
    */
    void setTextureCoordSet(unsigned int set);

    /** Sets a matrix used to transform any texture coordinates on this layer.
    @remarks
    Texture coordinates can be modified on a texture layer to create effects like scrolling
    textures. A texture transform can either be applied to a layer which takes the source coordinates
    from a fixed set in the geometry, or to one which generates them dynamically (e.g. environment mapping).
    @par
    It's obviously a bit impractical to create scrolling effects by calling this method manually since you
    would have to call it every framw with a slight alteration each time, which is tedious. Instead
    you can use the ControllerManager class to create a Controller object which will manage the
    effect over time for you. See the ControllerManager::createTextureScroller and it's sibling methods for details.<BR>
    In addition, if you want to set the individual texture transformations rather than concatenating them
    yourself, use setTextureScroll, setTextureScale and setTextureRotate.
    @note
    Has no effect in the programmable pipeline.
    */
    void setTextureTransform(const U2Matrix4& xform);

    /** Gets the current texture transformation matrix.
    @remarks
    Causes a reclaculation of the matrix if any parameters have been changed via
    setTextureScroll, setTextureScale and setTextureRotate.
    @note
    Has no effect in the programmable pipeline.
    */
    const U2Matrix4& getTextureTransform(void) const;

    /** Sets the translation offset of the texture, ie scrolls the texture.
    @remarks
    This method sets the translation element of the texture transformation, and is easier to use than setTextureTransform if
    you are combining translation, scaling and rotation in your texture transformation. Again if you want
    to animate these values you need to use a Controller
    @note
    Has no effect in the programmable pipeline.
    @param u The amount the texture should be moved horizontally (u direction).
    @param v The amount the texture should be moved vertically (v direction).
    @see
    ControllerManager, Controller
    */
    void setTextureScroll(u2real u, u2real v);

    /** As setTextureScroll, but sets only U value.
    @note
    Has no effect in the programmable pipeline.
    */
    void setTextureUScroll(u2real value);
    // get texture uscroll value
    u2real getTextureUScroll(void) const;

    /** As setTextureScroll, but sets only V value.
    @note
    Has no effect in the programmable pipeline.
    */
    void setTextureVScroll(u2real value);
    // get texture vscroll value
    u2real getTextureVScroll(void) const;

    /** As setTextureScale, but sets only U value.
    @note
    Has no effect in the programmable pipeline.
    */
    void setTextureUScale(u2real value);
    // get texture uscale value
    u2real getTextureUScale(void) const;

    /** As setTextureScale, but sets only V value.
    @note
    Has no effect in the programmable pipeline.
    */
    void setTextureVScale(u2real value);
    // get texture vscale value
    u2real getTextureVScale(void) const;

    /** Sets the scaling factor applied to texture coordinates.
    @remarks
    This method sets the scale element of the texture transformation, and is easier to use than
    setTextureTransform if you are combining translation, scaling and rotation in your texture transformation. Again if you want
    to animate these values you need to use a Controller (see ControllerManager and it's methods for
    more information).
    @note
    Has no effect in the programmable pipeline.
    @param
    uScale The value by which the texture is to be scaled horizontally.
    @param
    vScale The value by which the texture is to be scaled vertically.
    */
    void setTextureScale(u2real uScale, u2real vScale);

    /** Sets the anticlockwise rotation factor applied to texture coordinates.
    @remarks
    This sets a fixed rotation angle - if you wish to animate this, see the
    ControllerManager::createTextureRotater method.
    @note
    Has no effect in the programmable pipeline.
    @param
    angle The angle of rotation (anticlockwise).
    */
    void setTextureRotate(const Radian& angle);
    // get texture rotation effects angle value
    const Radian& getTextureRotate(void) const;

    /** Gets the texture addressing mode for a given coordinate, 
	 	i.e. what happens at uv values above 1.0.
    @note
    	The default is TAM_WRAP i.e. the texture repeats over values of 1.0.
    */
    const UVWAddressingMode& getTextureAddressingMode(void) const;

    /** Sets the texture addressing mode, i.e. what happens at uv values above 1.0.
    @note
    The default is TAM_WRAP i.e. the texture repeats over values of 1.0.
	@note This is a shortcut method which sets the addressing mode for all
		coordinates at once; you can also call the more specific method
		to set the addressing mode per coordinate.
    @note
    This applies for both the fixed-function and programmable pipelines.
    */
    void setTextureAddressingMode( TextureAddressingMode tam);

    /** Sets the texture addressing mode, i.e. what happens at uv values above 1.0.
    @note
    The default is TAM_WRAP i.e. the texture repeats over values of 1.0.
    @note
    This applies for both the fixed-function and programmable pipelines.
	*/
    void setTextureAddressingMode( TextureAddressingMode u, 
		TextureAddressingMode v, TextureAddressingMode w);

    /** Sets the texture addressing mode, i.e. what happens at uv values above 1.0.
    @note
    The default is TAM_WRAP i.e. the texture repeats over values of 1.0.
    @note
    This applies for both the fixed-function and programmable pipelines.
	*/
    void setTextureAddressingMode( const UVWAddressingMode& uvw);

    /** Sets the texture border colour.
    @note
        The default is U2ColourValue::Black, and this value only used when addressing mode
        is TAM_BORDER.
    @note
        This applies for both the fixed-function and programmable pipelines.
	*/
    void setTextureBorderColour(const U2ColourValue& colour);

    /** Sets the texture border colour.
    @note
        The default is U2ColourValue::Black, and this value only used when addressing mode
        is TAM_BORDER.
	*/
    const U2ColourValue& getTextureBorderColour(void) const;

	/** Setting advanced blending options.
    @remarks
    This is an extended version of the TextureUnitState::setColourOperation method which allows
    extremely detailed control over the blending applied between this and earlier layers.
    See the IMPORTANT note below about the issues between mulitpass and multitexturing that
    using this method can create.
    @par
    Texture colour operations determine how the final colour of the surface appears when
    rendered. Texture units are used to combine colour values from various sources (ie. the
    diffuse colour of the surface from lighting calculations, combined with the colour of
    the texture). This method allows you to specify the 'operation' to be used, ie. the
    calculation such as adds or multiplies, and which values to use as arguments, such as
    a fixed value or a value from a previous calculation.
    @par
    The defaults for each layer are:
    <ul>
    <li>op = LBX_MODULATE</li>
    <li>source1 = LBS_TEXTURE</li>
    <li>source2 = LBS_CURRENT</li>
    </ul>
    ie. each layer takes the colour results of the previous layer, and multiplies them
    with the new texture being applied. Bear in mind that colours are RGB values from
    0.0 - 1.0 so multiplying them together will result in values in the same range,
    'tinted' by the multiply. Note however that a straight multiply normally has the
    effect of darkening the textures - for this reason there are brightening operations
    like LBO_MODULATE_X2. See the LayerBlendOperation and LayerBlendSource enumerated
    types for full details.
    @note
    Because of the limitations on some underlying APIs (Direct3D included)
    the LBS_TEXTURE argument can only be used as the first argument, not the second.
    @par
    The final 3 parameters are only required if you decide to pass values manually
    into the operation, i.e. you want one or more of the inputs to the colour calculation
    to come from a fixed value that you supply. Hence you only need to fill these in if
    you supply LBS_MANUAL to the corresponding source, or use the LBX_BLEND_MANUAL
    operation.
    @warning
    Ogre tries to use multitexturing hardware to blend texture layers
    together. However, if it runs out of texturing units (e.g. 2 of a GeForce2, 4 on a
    GeForce3) it has to fall back on multipass rendering, i.e. rendering the same object
    multiple times with different textures. This is both less efficient and there is a smaller
    range of blending operations which can be performed. For this reason, if you use this method
    you MUST also call TextureUnitState::setColourOpMultipassFallback to specify which effect you
    want to fall back on if sufficient hardware is not available.
    @note
    This has no effect in the programmable pipeline.
    @param
    If you wish to avoid having to do this, use the simpler TextureUnitState::setColourOperation method
    which allows less flexible blending options but sets up the multipass fallback automatically,
    since it only allows operations which have direct multipass equivalents.
    @param
    op The operation to be used, e.g. modulate (multiply), add, subtract
    @param
    source1 The source of the first colour to the operation e.g. texture colour
    @param
    source2 The source of the second colour to the operation e.g. current surface colour
    @param
    arg1 Manually supplied colour value (only required if source1 = LBS_MANUAL)
    @param
    arg2 Manually supplied colour value (only required if source2 = LBS_MANUAL)
    @param
    manualBlend Manually supplied 'blend' value - only required for operations
    which require manual blend e.g. LBX_BLEND_MANUAL
    */
    void setColourOperationEx(
        LayerBlendOperationEx op,
        LayerBlendSource source1 = LBS_TEXTURE,
        LayerBlendSource source2 = LBS_CURRENT,

        const U2ColourValue& arg1 = U2ColourValue::White,
        const U2ColourValue& arg2 = U2ColourValue::White,

        u2real manualBlend = 0.0);

    /** Determines how this texture layer is combined with the one below it (or the diffuse colour of
    the geometry if this is layer 0).
    @remarks
    This method is the simplest way to blend tetxure layers, because it requires only one parameter,
    gives you the most common blending types, and automatically sets up 2 blending methods: one for
    if single-pass multitexturing hardware is available, and another for if it is not and the blending must
    be achieved through multiple rendering passes. It is, however, quite limited and does not expose
    the more flexible multitexturing operations, simply because these can't be automatically supported in
    multipass fallback mode. If want to use the fancier options, use TextureUnitState::setColourOperationEx,
    but you'll either have to be sure that enough multitexturing units will be available, or you should
    explicitly set a fallback using TextureUnitState::setColourOpMultipassFallback.
    @note
    The default method is LBO_MODULATE for all layers.
    @note
    This option has no effect in the programmable pipeline.
    @param
    op One of the LayerBlendOperation enumerated blending types.
    */
    void setColourOperation( const LayerBlendOperation op);

    /** Sets the multipass fallback operation for this layer, if you used TextureUnitState::setColourOperationEx
    and not enough multitexturing hardware is available.
    @remarks
    Because some effects exposed using TextureUnitState::setColourOperationEx are only supported under
    multitexturing hardware, if the hardware is lacking the system must fallback on multipass rendering,
    which unfortunately doesn't support as many effects. This method is for you to specify the fallback
    operation which most suits you.
    @par
    You'll notice that the interface is the same as the Material::setSceneBlending method; this is
    because multipass rendering IS effectively scene blending, since each layer is rendered on top
    of the last using the same mechanism as making an object transparent, it's just being rendered
    in the same place repeatedly to get the multitexture effect.
    @par
    If you use the simpler (and hence less flexible) TextureUnitState::setColourOperation method you
    don't need to call this as the system sets up the fallback for you.
    @note
    This option has no effect in the programmable pipeline, because there is no multipass fallback
    and multitexture blending is handled by the fragment shader.
    */
    void setColourOpMultipassFallback( const SceneBlendFactor sourceFactor, const SceneBlendFactor destFactor);

    /** Get multitexturing colour blending mode.
    */
    const LayerBlendModeEx& getColourBlendMode(void) const;

    /** Get multitexturing alpha blending mode.
    */
    const LayerBlendModeEx& getAlphaBlendMode(void) const;

    /** Get the multipass fallback for colour blending operation source factor.
    */
    SceneBlendFactor getColourBlendFallbackSrc(void) const;

    /** Get the multipass fallback for colour blending operation destination factor.
    */
    SceneBlendFactor getColourBlendFallbackDest(void) const;

    /** Sets the alpha operation to be applied to this texture.
    @remarks
    This works in exactly the same way as setColourOperation, except
    that the effect is applied to the level of alpha (i.e. transparency)
    of the texture rather than its colour. When the alpha of a texel (a pixel
    on a texture) is 1.0, it is opaque, whereas it is fully transparent if the
    alpha is 0.0. Please refer to the setColourOperation method for more info.
    @param
    op The operation to be used, e.g. modulate (multiply), add, subtract
    @param
    source1 The source of the first alpha value to the operation e.g. texture alpha
    @param
    source2 The source of the second alpha value to the operation e.g. current surface alpha
    @param
    arg1 Manually supplied alpha value (only required if source1 = LBS_MANUAL)
    @param
    arg2 Manually supplied alpha value (only required if source2 = LBS_MANUAL)
    @param
    manualBlend Manually supplied 'blend' value - only required for operations
    which require manual blend e.g. LBX_BLEND_MANUAL
    @see
    setColourOperation
    @note
    This option has no effect in the programmable pipeline.
    */
    void setAlphaOperation(LayerBlendOperationEx op,
        LayerBlendSource source1 = LBS_TEXTURE,
        LayerBlendSource source2 = LBS_CURRENT,
        u2real arg1 = 1.0,
        u2real arg2 = 1.0,
        u2real manualBlend = 0.0);

    /** Generic method for setting up texture effects.
    @remarks
    Allows you to specify effects directly by using the TextureEffectType enumeration. The
    arguments that go with it depend on the effect type. Only one effect of
    each type can be applied to a texture layer.
    @par
    This method is used internally by Ogre but it is better generally for applications to use the
    more intuitive specialised methods such as setEnvironmentMap and setScroll.
    @note
    This option has no effect in the programmable pipeline.
    */
    void addEffect(TextureEffect& effect);

    /** Turns on/off texture coordinate effect that makes this layer an environment map.
    @remarks
    Environment maps make an object look reflective by using the object's vertex normals relative
    to the camera view to generate texture coordinates.
    @par
    The vectors generated can either be used to address a single 2D texture which
    is a 'fish-eye' lens view of a scene, or a 3D cubic environment map which requires 6 textures
    for each side of the inside of a cube. The type depends on what texture you set up - if you use the
    setTextureName method then a 2D fisheye lens texture is required, whereas if you used setCubicTextureName
    then a cubic environemnt map will be used.
    @par
    This effect works best if the object has lots of gradually changing normals. The texture also
    has to be designed for this effect - see the example spheremap.png included with the sample
    application for a 2D environment map; a cubic map can be generated by rendering 6 views of a
    scene to each of the cube faces with orthogonal views.
    @note
    Enabling this disables any other texture coordinate generation effects.
    However it can be combined with texture coordinate modification functions, which then operate on the
    generated coordinates rather than static model texture coordinates.
    @param
    enable True to enable, false to disable
    @param
    planar If set to true, instead of being based on normals the environment effect is based on
    vertex positions. This is good for planar surfaces.
    @note
    This option has no effect in the programmable pipeline.
    */
    void setEnvironmentMap(bool enable, EnvMapType envMapType = ENV_CURVED);

    /** Sets up an animated scroll for the texture layer.
    @note
    Useful for creating constant scrolling effects on a texture layer (for varying scrolls, see setTransformAnimation).
    @param
    uSpeed The number of horizontal loops per second (+ve=moving right, -ve = moving left)
    @param
    vSpeed The number of vertical loops per second (+ve=moving up, -ve= moving down)
    @note
    This option has no effect in the programmable pipeline.
    */
    void setScrollAnimation(u2real uSpeed, u2real vSpeed);

    /** Sets up an animated texture rotation for this layer.
    @note
    Useful for constant rotations (for varying rotations, see setTransformAnimation).
    @param
    speed The number of complete anticlockwise revolutions per second (use -ve for clockwise)
    @note
    This option has no effect in the programmable pipeline.
    */
    void setRotateAnimation(u2real speed);

    /** Sets up a general time-relative texture modification effect.
    @note
    This can be called multiple times for different values of ttype, but only the latest effect
    applies if called multiple time for the same ttype.
    @param
    ttype The type of transform, either translate (scroll), scale (stretch) or rotate (spin)
    @param
    waveType The shape of the wave, see WaveformType enum for details
    @param
    base The base value for the function (range of output = {base, base + amplitude})
    @param
    frequency The speed of the wave in cycles per second
    @param
    phase The offset of the start of the wave, e.g. 0.5 to start half-way through the wave
    @param
    amplitude Scales the output so that instead of lying within 0..1 it lies within 0..1*amplitude for exaggerated effects
    @note
    This option has no effect in the programmable pipeline.
    */
    void setTransformAnimation( const TextureTransformType ttype,
        const WaveformType waveType, u2real base = 0, u2real frequency = 1, u2real phase = 0, u2real amplitude = 1 );


    /** Enables or disables projective texturing on this texture unit.
    @remarks
        Projective texturing allows you to generate texture coordinates 
        based on a U2Frustum, which gives the impression that a texture is
        being projected onto the surface. Note that once you have called
        this method, the texture unit continues to monitor the U2Frustum you 
        passed in and the projection will change if you can alter it. It also
        means that you must ensure that the U2Frustum object you pass a pointer
        to remains in existence for as long as this TextureUnitState does.
    @par
        This effect cannot be combined with other texture generation effects, 
        such as environment mapping. It also has no effect on passes which 
        have a vertex program enabled - projective texturing has to be done
        in the vertex program instead.
    @param enabled Whether to enable / disable
    @param projectionSettings The U2Frustum which will be used to derive the 
        projection parameters.
    */
    void setProjectiveTexturing(bool enabled, const U2Frustum* projectionSettings = 0);

    /** Removes all effects applied to this texture layer.
    */
    void removeAllEffects(void);

    /** Removes a single effect applied to this texture layer.
    @note
    Because you can only have 1 effect of each type (e.g. 1 texture coordinate generation) applied
    to a layer, only the effect type is required.
    */
    void removeEffect( const TextureEffectType type );

    /** Determines if this texture layer is currently blank.
    @note
    This can happen if a texture fails to load or some other non-fatal error. Worth checking after
    setting texture name.
    */
    bool isBlank(void) const;

    /** Sets this texture layer to be blank.
    */
    void setBlank(void);

	/** Tests if the texture associated with this unit has failed to load.
	*/
	bool isTextureLoadFailing() const { return mTextureLoadFailed; }

	/** Tells the unit to retry loading the texture if it had failed to load.
	*/
	void retryTextureLoad() { mTextureLoadFailed = false; }

    // get texture effects in a multimap paired array
    const EffectMap& getEffects(void) const;
    // get the animated-texture animation duration
    u2real getAnimationDuration(void) const;

    /** Set the texture filtering for this unit, using the simplified interface.
    @remarks
        You also have the option of specifying the minification, magnification
        and mip filter individually if you want more control over filtering
        options. See the alternative setTextureFiltering methods for details.
    @note
    This option applies in both the fixed function and the programmable pipeline.
    @param filterType The high-level filter type to use.
    */
    void setTextureFiltering(TextureFilterOptions filterType);
    /** Set a single filtering option on this texture unit. 
    @params ftype The filtering type to set
    @params opts The filtering option to set
    */
    void setTextureFiltering(FilterType ftype, FilterOptions opts);
    /** Set a the detailed filtering options on this texture unit. 
    @params minFilter The filtering to use when reducing the size of the texture. 
        Can be FO_POINT, FO_LINEAR or FO_ANISOTROPIC
    @params magFilter The filtering to use when increasing the size of the texture
        Can be FO_POINT, FO_LINEAR or FO_ANISOTROPIC
    @params mipFilter The filtering to use between mip levels
        Can be FO_NONE (turns off mipmapping), FO_POINT or FO_LINEAR (trilinear filtering)
    */
    void setTextureFiltering(FilterOptions minFilter, FilterOptions magFilter, FilterOptions mipFilter);
    // get the texture filtering for the given type
    FilterOptions getTextureFiltering(FilterType ftpye) const;

    /** Sets the anisotropy level to be used for this texture level.
    @par maxAniso The maximal anisotropy level, should be between 2 and the maximum supported by hardware (1 is the default, ie. no anisotrophy).
    @note
    This option applies in both the fixed function and the programmable pipeline.
    */
    /**********************@@@@@@@@@@@@@@@@@@@@@
    void setTextureAnisotropy(unsigned int maxAniso);
    // get this layer texture anisotropy level
    unsigned int getTextureAnisotropy() const;
    */

	/** Sets the bias value applied to the mipmap calculation.
	@remarks
		You can alter the mipmap calculation by biasing the result with a 
		single floating point value. After the mip level has been calculated,
		this bias value is added to the result to give the final mip level.
		Lower mip levels are larger (higher detail), so a negative bias will
		force the larger mip levels to be used, and a positive bias
		will cause smaller mip levels to be used. The bias values are in 
		mip levels, so a -1 bias will force mip levels one larger than by the
		default calculation.
	@param bias The bias value as described above, can be positive or negative.
	*/
	void setTextureMipmapBias(float bias) { mMipmapBias = bias; }
	/** Gets the bias value applied to the mipmap calculation.
	@see TextureUnitState::setTextureMipmapBias
	*/
	float getTextureMipmapBias(void) const { return mMipmapBias; }

	/** Set the compositor reference for this texture unit state.
	@remarks 
		Only valid when content type is compositor.
	@param compositorName the name of the compositor to reference
	@param textureName the name of the texture to reference
	@param mrtIndex the index of the wanted texture, if referencing an MRT
	*/
	void setCompositorReference(const U2String& compositorName, const U2String& textureName, size_t mrtIndex = 0);

	/** Gets the name of the compositor that this texture referneces */
	const U2String& getReferencedCompositorName() const { return mCompositorRefName; }
	/** Gets the name of the texture in the compositor that this texture references */
	const U2String& getReferencedTextureName() const { return mCompositorRefTexName; }
	/** Gets the MRT index of the texture in the compositor that this texture references */ 
	size_t getReferencedMRTIndex() const { return mCompositorRefMrtIndex; }

    /**********************@@@@@@@@@@@@@@@@@@@@@
    /// Gets the parent Pass object
    Pass* getParent(void) const { return mParent; }
    */

	/** Internal method for preparing this object for load, as part of Material::prepare*/
	void _prepare(void);
	/** Internal method for undoing the preparation this object as part of Material::unprepare*/
	void _unprepare(void);
	/** Internal method for loading this object as part of Material::load */
	void _load(void);
	/** Internal method for unloading this object as part of Material::unload */
	void _unload(void);
    /// Returns whether this unit has texture coordinate generation that depends on the camera
    bool hasViewRelativeTextureCoordinateGeneration(void) const;

    // Is this loaded?
    bool isLoaded(void) const;
    /**********************@@@@@@@@@@@@@@@@@@@@@
    /// Tells the class that it needs recompilation.
    void _notifyNeedsRecompile(void);
    */

    /** Set the name of the Texture Unit State
    @remarks
        The name of the Texture Unit State is optional.  Its useful in material scripts where a material could inherit
        from another material and only want to modify a particalar Texture Unit State.
    */
    void setName(const U2String& name);
    /// get the name of the Texture Unit State
    const U2String& getName(void) const { return mName; }

    /** Set the alias name used for texture frame names
    @param name can be any sequence of characters and does not have to be unique           
    */
    void setTextureNameAlias(const U2String& name);
    /** gets the Texture Name Alias of the Texture Unit.
    */
    const U2String& getTextureNameAlias(void) const { return mTextureNameAlias;}

    /** Applies texture names to Texture Unit State with matching texture name aliases.
        If no matching aliases are found then the TUS state does not change.
    @remarks
        Cubic, 1d, 2d, and 3d textures are determined from current state of the Texture Unit.
        Assumes animated frames are sequentially numbered in the name.
        If matching texture aliases are found then true is returned.

    @param
        aliasList is a map container of texture alias, texture name pairs
    @param
        apply set true to apply the texture aliases else just test to see if texture alias matches are found.
    @return
        True if matching texture aliases were found in the Texture Unit State.
    */
    bool applyTextureAliases(const AliasTextureNamePairList& aliasList, const bool apply = true);

	/** Notify this object that its parent has changed */
    /**********************@@@@@@@@@@@@@@@@@@@@@
	void _notifyParent(Pass* parent);
    */

	/** Get the texture pointer for the current frame. */
	const U2TexturePtr& _getTexturePtr(void) const;
	/** Get the texture pointer for a given frame. */
	const U2TexturePtr& _getTexturePtr(size_t frame) const;

	/** Set the texture pointer for the current frame (internal use only!). */
	void _setTexturePtr(const U2TexturePtr& texptr);
	/** Set the texture pointer for a given frame (internal use only!). */
	void _setTexturePtr(const U2TexturePtr& texptr, size_t frame);

	/** Gets the animation controller (as created because of setAnimatedTexture)
		if it exists.
	*/
	Controller<u2real>* _getAnimController() const { return mAnimController; }

protected:
    // State
    /// The current animation frame.
    unsigned int mCurrentFrame;

    /// Duration of animation in seconds
    u2real mAnimDuration;            
    bool mCubic; // is this a series of 6 2D textures to make up a cube?
	
    TextureType mTextureType; 
    PixelFormat mDesiredFormat;
	int mTextureSrcMipmaps; // Request number of mipmaps

    unsigned int mTextureCoordSetIndex;
    UVWAddressingMode mAddressMode;
    U2ColourValue mBorderColour;

    LayerBlendModeEx mColourBlendMode;
    SceneBlendFactor mColourBlendFallbackSrc;
    SceneBlendFactor mColourBlendFallbackDest;

    LayerBlendModeEx mAlphaBlendMode;
    mutable bool mTextureLoadFailed;
    bool mIsAlpha;
	bool mHwGamma;

    mutable bool mRecalcTexMatrix;
    u2real mUMod, mVMod;
    u2real mUScale, mVScale;
    Radian mRotate;
    mutable U2Matrix4 mTexModMatrix;

    /// Texture filtering - minification
    FilterOptions mMinFilter;
    /// Texture filtering - magnification
    FilterOptions mMagFilter;
    /// Texture filtering - mipmapping
    FilterOptions mMipFilter;
    /**********************@@@@@@@@@@@@@@@@@@@@@
    ///Texture anisotropy
    unsigned int mMaxAniso;
    */
	/// Mipmap bias (always float, not u2real)
	float mMipmapBias;

    bool mIsDefaultAniso;
    bool mIsDefaultFiltering;
	/// Binding type (fragment or vertex pipeline)
	BindingType mBindingType;
	/// Content type of texture (normal loaded texture, auto-texture)
	ContentType mContentType;
	/// The index of the referenced texture if referencing an MRT in a compositor
	size_t mCompositorRefMrtIndex;

    //-----------------------------------------------------------------------------
    // Complex members (those that can't be copied using memcpy) are at the end to 
    // allow for fast copying of the basic members.
    //
    std::vector<U2String> mFrames;
    mutable std::vector<U2TexturePtr> mFramePtrs;
    U2String mName;               // optional name for the TUS
    U2String mTextureNameAlias;       // optional alias for texture frames
    EffectMap mEffects;
	///The data that references the compositor
	U2String mCompositorRefName;
	U2String mCompositorRefTexName;
    //-----------------------------------------------------------------------------

    //-----------------------------------------------------------------------------
    // Pointer members (those that can't be copied using memcpy), and MUST
    // preserving even if assign from others
    //
    /**********************@@@@@@@@@@@@@@@@@@@@@
    Pass* mParent;
    */
    U2String mResourceGroup;
    Controller<u2real>* mAnimController;
    //-----------------------------------------------------------------------------


    /** Internal method for calculating texture matrix.
    */
    void recalcTextureMatrix(void) const;

    /** Internal method for creating animation controller.
    */
    void createAnimController(void);

    /** Internal method for creating texture effect controller.
    */
    void createEffectController(TextureEffect& effect);

	/** Internal method for ensuring the texture for a given frame is prepared. */
	void ensurePrepared(size_t frame) const;
	/** Internal method for ensuring the texture for a given frame is loaded. */
	void ensureLoaded(size_t frame) const;


};


U2EG_NAMESPACE_END


#endif
